1. Field of the Invention
The present invention relates to an outdoor lighting device, and in particular to an outdoor lighting device that features lighting realized by an array of lighting elements and internally concealed direct-current (DC) power supply for providing outdoor lighting.
2. The Related Arts
Conventional outdoor lighting devices, such as street lamps, walkway lights and alameda lights, are commonly used for outdoor lighting. To protect the environment and to save power, the conventional lighting devices, which are often operated with DC bulbs or alternate-current (AC) mercury vapor lamp, are gradually replaced by DC outdoor lighting devices that are operated with light-emitting diodes (LEDs). The conventional LED based DC outdoor lighting devices is often comprised of a plurality of individual LEDs that is arranged in an array for enhancing the illuminating brightness. This makes the cost very high. In addition, each LED needs a respective shade or cover and this often causes interference between adjacent LEDs and makes the control of lighting difficult, and it is difficult for secondary optic processing, and eventually leads to adverse influence to the development of the industry and marketing of product. Further, another problem occurring in composing multiple individual LEDs to form an outdoor lighting device resides in that a power supply is required and the power supply is arranged outside the outdoor lighting device. In other words, the power supply device and the lighting device are separate devices. This makes the installation of the outdoor lighting device very troublesome and an additional space for the power supply device must be taken into consideration. Besides, the power supply device that is located outside the outdoor lighting device is subject to damages caused by weathering and thunder lighting and is easily attacked by invasion of humidity and dusk, leading to shorting and corrosion of parts. Consequently, the power supply device of the conventional outdoor lighting device is of an extreme percentage of malfunctions after a period of service, leading to additional expense for maintenance and repairing. All these make the conventional outdoor lighting devices shortened lifespan, reduced reliability, and poor usability, adding adverse factors to the industry of outdoor lighting devices.